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Correlates of dissociative symptoms among women with eating disorders
~
J. psychiat.Res., Vol.29, No. 5. pp. 417~126, 1995 Copyright© 1995ElsevierScienceLtd Printedin Great Britain.All rightsreserved 0022 3956/95$9.50+.00
Pergamon 0022-3956(95)00016-X
CORRELATES OF DISSOCIATIVE SYMPTOMS AMONG WOMEN WITH EATING DISORDERS DAVID H. GLEAVES*t and KATHLEEN P. EBERENZt:~ * Department of Psychology, Texas A & M University, College Station, TX 77843, U.S.A.; t Research Department, The Renfrew Foundation, 475 Spring Lane, Philadelphia, PA 19128, U.S.A; and ++Department of Clinical and Health Psychology, Medical College of Pennsylvania and Hahnemann University, Philadelphia PA 19102, U.S.A.
(Received 19 September 1994; accepted 28 February 1995) Summary--We examined the relationship between dissociative symptoms and other Axis I and Axis II symptoms among a sample of 53 women diagnosed as having anorexia nervosa (n = 18), bulimia nervosa (n = 27), or eating disorder NOS (n = 8). Dissociative symptoms were measured by the Dissociative Experiences Scale and the dissociation scale from the Trauma Symptom Checklist40. Severity of dissociative symptoms was generally unrelated to severity of bulimic or anorexic symptomatology but was significantly associated with severity of anxiety and depression. In terms of Axis II symptoms, dissociative symptoms were most highly correlated with schizotypal symptomatology (r = .59), uncorrelated with borderline or antisocial symptomatology, and slightly negatively correlated with histrionic symptomatology.
Introduction Recently, several researchers and clinicians have described or studied dissociative symptoms or dissociative disorders among patients with eating disorders (Demitrack et al., 1990; McCallum et al., 1992; Torem, 1986, 1990, 1993; Vanderlinden et al., 1993). Groups of eating disorder patients have generally been found to exhibit an above normal level of dissociative symptomatology. Less is known about why such symptoms are present and how the dissociative symptoms relate to the other psychopathology of the disorder, including specific eating disorder symptoms (e.g. starvation and bulimia) co-morbid Axis I symptomatology (e.g. depression and anxiety), and Axis II symptomatoiogy. In a previous investigation where the connection between dissociation and other psychopathology among eating disordered individuals was examined, Demitrack et al. (1990) found dissociative symptomatology to be positively correlated with depression, anxiety, self-mutilation, and suicidality. The authors also found no significant differences between anorexia and bulimia nervosa samples in terms of dissociative symptoms; however, they did not did not examine the connection between severity of dissociation and eating disorder symptomatology. More recently, Greenes et al. (1993) also found a significant relationship between depression and dissociation in patients with bulimia nervosa. The authors noted that such an association may confound the previously suggested relationship between bulimia and dissociation. That is, it is unclear whether elevated levels of dissociative Correspondence to: David H. Gleaves, Ph.D., Department of Psychology, Texas A&M University, College Station, TX 77843, U.S.A. 417
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symptoms among eating disordered samples is due to some connection between eating disorders and dissociation per se, or whether such elevations are an artifact of an association between dissociation and depression. Since Demitrack et al. (1990) also reported an association between anxiety and dissociation, anxiety may be another confounding variable. Another relevant and possibly confounding variable may be personality disorder pathology. Personality disorders, especially of a borderline type, commonly occur among patients with eating disorders (e.g. Gartner et al., 1989). Dissociative symptoms may also be associated with certain personality disorders. Severe dissociative symptoms are now included as a diagnostic criterion for borderline personality disorder in the DSM-IV (American Psychiatric Association, 1994). Many researchers and clinicians have also described dissociative symptoms (and dissociative disorders) as being attention seeking and hysterical in nature (e.g. Fahy, 1988) or as being associated with antisocial personality disorders (e.g. North et al., 1993). Thus, if dissociative symptoms are highly associated with such personality disorder pathology, then dissociative symptoms among eating disordered samples may be an artifact of such an association. However, the described associations between dissociative and personality disorder symptomatology have not been demonstrated empirically. In summary, at least two issues regarding dissociative symptoms and eating disorders appear unresolved. It is unclear whether dissociative symptoms reported by eating disordered patients are in some way directly related to the specific psychopathology of eating disorders, or whether elevated levels of dissociative symptoms are due to their association with depression, anxiety, or personality disorder pathology. The nature of the relationship between dissociative symptoms and personality disorder pathology also remains untested. The purpose of the current investigation was to examine empirically the relationship between dissociative experiences and other clinical variables among women with eating disorders. Specific goals were: (1) to determine the specific relationship between dissociative symptoms and anorexic and bulimic symptomatology; (2) to replicate previous findings regarding an association between dissociation and both depression and anxiety; and (3) to examine the association between dissociative symptoms and personality disorder pathology. Method
Subjects Fifty-three women who were in treatment at a residential facility for eating disorders served as subjects. The women's ages ranged from 15 to 50 years, with a mean of 26.5 years and a standard deviation of 7.9. They were diagnosed, based on DSM-III-R criteria (American Psychiatric Association, 1987), as having anorexia nervosa (n = 18), bulimia nervosa (n = 27), or eating disorder NOS (n = 8). Normative data for the sample, based on the Eating Disorder Inventory (see below), are presented in Table 1. By examining percentile scores, one can see that the sample was, for the most part, in the average to slightly above average severity range.
Materials A variety of self-report measures was included in the study. Dissociative symptoms were measured by the Dissociative Experiences Scale (DES; Bernstein & Putnam, 1986) and the
Correlates of Dissociative Symptoms
419
Table 1 Subjects' Raw and Percentile Scores on the Eating Disorder Inventor),
AN
BN
EDNOS
DT B BD
16.2 (53) 2.7 (12) 16.9 (49)
16.6 (61) 12.7 (67) 19.8 (60)
10.7 (27) 9.6 (51) 19.9 (60)
I
13.6 (66)
13.0 (62)
12.1 (58)
P ID IA MF
8.5 (54) 8.1 (72) 11.7 (62) 4.1 (65)
10.7 (67) 6.6 (67) 14.3 (70) 4.7 (71)
8.1 (47) 6.1 (60) 8.9 (47) 5.3 (71)
Values in parentheses are approximate percentile scores for eating disordered patients (from Garner, 1991). Dissociation scale from the T r a u m a Symptom Checklist (Elliot & Briere, 1992). These two instruments have been found to demonstrate good convergent validity (r = .73; Gleaves & Eberenz, 1995). Eating disorder symptoms were measured by the Eating Disorder Inventory-2 (EDI-2; Garner, 1991), the Eating Attitudes Test (EAT; Garner & Garfinkel, 1979), and the Bulimia T e s t - Revised (BULIT-R; Thelen et al., 1991). The Beck Depression Inventory (BDI; Beck et al., 1988), and the Minnesota Multiphasic Personality Inventory2 (MMPI-2; H a t h a w a y & McKinley, 1989) were also administered. For this investigation, only the personality disorder scales from the M M P I - 2 (Colligan et al., 1994; Morey et al., 1988) were examined. D a t a based on the clinical scales were presented in a previous investigation (Phillips & Gleaves, 1994). Design and procedures
Patients' diagnoses were made by a masters level admission team member using a semistructured interview. Diagnoses were then confirmed by the patient's individual therapist who was a clinical psychologist or psychiatrist. All of the assessment instruments were included in an intake packet which was administered when the patient was admitted to the hospital. The patients were then instructed to complete the packet during their first few days in the hospital. Results The subjects' scores on the DES and TSC-40-DIS are presented in Table 2a. For descriptive purposes, DES factor scores derived from Ross et al. (1991) are also presented, but were not included in subsequent analyses, since they were not relevant to the specific hypotheses of this study. Total scores for the two dissociation instruments were found to be highly intercorrelated (r = .76), suggesting good convergent validity. The different diagnostic groups were initially compared on the dissociation measures Only data that were relevant to our specific hypothesis were presented. The EDI-2 and TSC-40, EAT, and MMPI-2 contain subscales that were not presented. Information on any of these data can be obtained by contacting the first author.
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using a multivariate analysis of variance (MANOVA). Group means for the two dissociation scales are presented in Table 2b. Based on Wilk's criterion, the MANOVA was non-significant [F(4, 98) = . 14, p > .05], suggesting that the groups did not differ in terms of dissociative symptomsfl Thus, the different diagnostic groups were combined for all subsequent analyses. The univariate relationships between clinical variables were measured via Pearson product moment coefficients (Pearson correlations). Correlations between the dissociation measures and those measuring Axis I symptoms (anorexia, bulimia, depression, and anxiety) symptoms are presented in Table 3. Significance levels at p < .01 and p < .001 are noted. Since several correlations were calculated, a more conservative alpha level was used to control for Type I errors. We then performed a stepwise multiple regression analysis with dissociative symptoms as the criterion and the other symptom variables as predictors. We first created a principal component variable from the DES and TSC-Dissociation scales which was used as the dependent variable in the regression analysis. The two scales were highly correlated (r = .76) and generated a principal component that explained 88% of the variance from the two sales. In the multiple regression analysis, the first variable to enter the equation was the anxiety scale from the TSC-40, since it had the highest zero-order correlation. On the second step, Table 2a Subjects' Range of Scores on the Dissociation Scales
TSC-40-DIS DES Total DES Factor 1 DES Factor 2 DES Factor 3
Mean
SD
Min
Max
6.6 12.5 19.5 2.3 9.7
4.5 12.0 16.8 4.6 15.4
0.0 0.5 0.8 0.0 0.0
18 52.3 72.5 23.8 74.0
TSC-40-DIS, Dissociation scale from the Trauma Symptom Checklist; DES, Dissociative Experiences Scale; Factor 1, depersonalization/derealization; 2, activities in dissociative states; 3, absorption. Table 2b Group Means (and Standard Deviations)for the Dissociation Scales
DES TSC-40-DIS
AN
BN
EDNOS
12.2 (13.8)
13.1 (10.1)
11.2 (11.2)
6.2 (3.9)
6.9 (4.7)
6.5 (5.6)
One reviewer was concerned that meaningful associations between variables might have been obscured by combining all of the subject into one group. For example, this might have occurred if two variables were positively correlated in one sample and negatively correlated in another. To rule out this possibility, we examined all reported correlations separately for the three groups. Although values changes slightly, the pattern of correlations was unchanged, which seemed to justify further the use of the entire sample.
Correlates of Dissociative Symptoms
421
Table 3 Correlations Between Dissociative Scales and Other Axis 1 Symptoms Scales DES Anorexia measures E A T Total EDI Drive for Thinness Bulimia Measures Bulimia Test--Revised EDI Bulimia Depression measures BDI TSC-40-DEP Anxiety measures TSC-40-ANX MMPI-MSA
TSC-40-DIS
.25 .25
.43* .38*
.11 .14
.07 .01
.55** .41 *
.52** .44*
.47'* .49**
.68"* .51 **
EAT, Eating Attitudes Test; EDI, Eating Disorder Inventory-2; BUL1T-R, Bulimia Test--Revised. *p < .01; **p < .001.
the BDI was added to the equation. After accounting for these first two variables, all other partial correlations were non-significant. Thus, no other variables were added to the equation. The two variables accounted for 44% of the total variance in dissociative symptoms. Beta weights for the TSC-40 anxiety scale and the BDI were .42 and .32, respectively, suggesting that the anxiety scale contributed greater unique variance. Correlations between the dissociation scales and the personality disorder scales from the MMPI-2 are presented in Table 4. As can be seen, there were numerous significant correlations. We then performed a second stepwise regression analysis using the personality disorder Table 4 Correlations Between Dissociation Scales and MMPI-2 Personality Disorder Scales
MMPI-2 Scale Histrionic Narcissistic Borderline Antisocial Dependent Compulsive Passive Aggressive Paranoid Schizotypal Avoidant Schizoid
DES
TSC-40-DIS
- .26 -.10 .22 .15 .38* .34 .47** .49"* .50** .43* .35
- .36* - .07 .I 1 .13 .23 .38* .53** .45"* .59** .50** .41 *
DES, Dissociative Experiences Scale; TSC-40-DIS, Dissociation scale from the T r a u m a Symptom Checklist. *p < .01; **p < . 0001.
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D . H . Gleaves and K. P. Eberenz
scales as predictor variables. Because of its highest zero-order correlation, the schizotypal scale was the first variable entered into the equation. After accounting for this scale, the passive aggressive scale was entered. After accounting for these two variables, no other partial correlations were statistically significant. Thus, no other variables could be added to the equation. The two variables accounted for 40% of the total variance in dissociative symptoms. Beta weights for the schizotypal and passive aggressive scales were .42 and .30, suggesting that the former contributed greater unique variance in predicting dissociative symptoms. We then performed a third stepwise regression analysis using the four variables that were derived from the first two analyses: the TSC-40 anxiety scale, the BDI, and the schizotypal and passive aggressive scales from the MMPI-2. The anxiety scale was again the first entered in the equation, followed by the schizotypal scale from the MMPI-2. These two variables accounted for 51% of the variance in the dissociative symptoms, and beta weights for the anxiety and schizotypal scales were .45 and .40, respectively, suggesting that they both contributed a sizeable amount of unique variance. After accounting for these two variables, the partial correlations for the other two variables were non-significant.
Discussion A principal goal of this investigation was to examine the relationship between dissociative symptoms and anorexic and bulimic symptomatology. Bulimic behavior appeared to be totally uncorrelated with dissociative symptoms. None of the zero-order correlations was statistically significant (at the predetermined alpha level). Some of the zero-order correlations between the anorexic symptom variables and the dissociation scales were significant. However, after accounting for the depression and anxiety variables (in the stepwise regression procedures) none of the correlations was significant. Thus, these data do not suggest that dissociative symptoms are related to the core symptomatology of eating disorders. The findings support the hypothesis by Greenes (1993) that previously obtained findings may have been confounded. However, the current findings should be interpreted with caution, given the correlational nature of the data. The data suggest that, across a group of eating disordered individuals, severity of dissociative symptoms does not co-vary with severity of eating disordered symptoms. The data cannot be interpreted to mean that individual eating disordered patients do not experience dissociative symptoms associated with bingeing, purging, or other eating disordered behavior. These results did replicate those of Demitrack et al. (1990) regarding the association between dissociation and both anxiety and depression. The results of the third regression analysis found anxiety to be a slightly better predictor of dissociation than was depression. Regarding this high correlation between dissociation and both anxiety and depression, such data might lead one to question (as did one reviewer) whether or not the dissociation scales were actually simply measuring depression or anxiety. That is, do the findings question the construct validity of the dissociation scales? For two reasons, we believe that available data do support the construct validity of the scales. First, the convergent validity coefficient (the correlation between the two scales) was substantially higher (r = .76) than
Correlates of DissociativeSymptoms
423
the correlations between either of the dissociation scales and the depression or anxiety scales (seven out of eight were below .60 and four out of eight were below .50). The only one that was even in the same range was the correlation between the TSC-40-DIS and TSC40-ANX scales (r = .68), which might be somewhat inflated owing to their coming from the same test. The second source of data was a previous study (Gleaves & Eberenz, 1995) in which the construct validity of the same two scales was tested by examining convergent and discriminant validity coefficients (when administered along with instruments measuring other constructs) as well as by factor analytic strategies. The results of both types of analyses supported the construct validity of the two instruments. The current findings regarding the relationship between dissociation and Axis II symptoms were quite interesting. The strongest predictor of dissociative symptoms was the schizotypal scale. This finding was not surprising, given the nature of the items on the scale and the nature of schizotypal symptomatology. Items on the MMPI-2 scale assess odd sensory experiences (e.g. "I have had very peculiar and strange experiences", "I have strange and peculiar thoughts"), depersonalization and derealization ("My soul sometimes leaves my body" and "I often feel as if things are not real") and Schneiderian-type influence phenomena ("Evil spirits possess me at times"), all of which are features generally associated with dissociative disorders (e.g. Loewenstein, 1991). Several of the other personality disorder scales were also significantly correlated with the dissociation measures. However, when stepwise regression procedures were employed, schizotypal appeared to be the strongest predictor. This was not surprising, given the degree of overlap among the scales and constructs. For example, in addition to the symptoms described above, schizotypal personality disorder is characterized by excessive social anxiety and avoidance (which overlaps with avoidant, dependent, and schizoid personality disorders) and suspiciousness (which overlaps with paranoid personality disorder). Thus, the schizotypat scale alone appeared to measure most of the Axis II characteristics that were associated with dissociative symptoms: odd perceptual experiences (including depersonalization/derealization and influence phenomena), excessive anxiety and social avoidance, and distrust of others. The hypothesis that dissociative symptoms are strongly associated with features of borderline or antisocial personality disorders was not supported by these data. Neither of the dissociation measures was significantly correlated with either the borderline or antisocial scales of the MMPI-2. We should note that the failure to find significant correlations with either of these scales was not due to lack of variability on the scales. Both scales were significantly correlated with several of the other personality disorder scales. This finding that the dissociation scales did not correlate with either the borderline or antisocial scales does not suggest that individuals with dissociative disorders cannot have a comorbid borderline or antisocial personality disorder. As with other Axis I conditions, dissociative disorders can be associated with a variety of Axis II symptoms or disorders, and research has shown that dissociative disorders and borderline personality disorder frequently co-occur (e.g. Horevitz & Braun, 1984). However, the finding does suggest that the specific symptomatology of dissociative disorders is distinct from that of borderline or antisocial personality disorders.
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The finding regarding borderline symptomatology is consistent with a recent investigation by Cancienne et al. (1993) who examined dissociative symptoms among patients with borderline personality disorder with and without a history of sexual abuse. Both borderline groups were compared with normal controls. The results suggested that dissociative symptoms were not associated with borderline personality disorder per se, but were associated with a history of sexual abuse. Thus, the findings suggest that dissociative symptoms that have been reported to be associated with borderline personality disorder may actually be an artifact of a comorbid post-traumatic condition. In the current study, both dissociation scales were actually slightly negatively correlated with the histrionic scale (although the correlation was significant for only the TSC-40-DIS). Histrionic personality disorder (formerly termed hysterical personality) is characterized by excessive emotionality and attention seeking (APA, 1994). Thus, the hypotheses that dissociative symptoms are hysterical in nature and that patients with dissociative disorders are frequently attention-seeking individuals were not supported by these data. On the contrary, the negative correlations with the histrionic scale and the positive correlations with the avoidant, schizoid, and schizotypal scales (which are all associated with avoidance behaviors) suggest that (at least within this clinical population) individuals who report dissociative symptoms have more of a tendency towards avoidance and withdrawal. This finding supports the position taken by many clinicians and researchers in the field of dissociation that the dissociative disorders may be clandestine by nature (Kluft, 1991). A limitation of this study was that only one measure of personality disorder symptomatology (the MMPI) was used. Future research could strengthen these findings by using other indices of Axis II symptomatology (e.g. the Millon Clinical Multiaxial Inventory). A larger sample size using other types of clinical and non-clinical subjects would also help to determine the stability and generalizability of the current findings. Another limitation was that structured interviews were not used to determine whether patients met the diagnostic criteria for either dissociative or personality disorders. Thus, the findings only specifically addressed dissociative and personality disorder symptomatology, and we cannot confidently generalize to the issue of dissociative or personality disorders. Future research could attempt to do so using well-validated interview schedules (e.g. Steinberg et al., 1993). A final limitation was that we only examined a linear relationship between dissociative and other experiences. It is possible that other relationships (e.g. curvilinear or quadratic) may exist and may lead to more meaningful interpretations of the data. However, because we had no a priori hypotheses regarding such effect, it was inappropriate to have tested for them since that may have led to spurious findings. Future research might endeavor to test such relationships if theoretical rationale can be presented for doing so. In conclusion, these data somewhat further our current understanding of the phenomenon of dissociation and its relationship with other variables among women with eating disorders. Dissociative symptoms do not appear to be strongly associated with eating disorder symptoms per se, but are associated with a wealth of comorbid Axis I and Axis II symptoms. The associations with Axis II symptoms, however, appear to be different from what has been most commonly hypothesized in the clinical literature.
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References American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington DC: American Psychiatric Association. Beck, A. T., Steer, R. A., & Garbin, M. G. (1988). Psychometric properties of the Beck Depression Inventory: Twenty-five years of evaluation. Clinical Psychology Review, 8, 77 100. Bernstein, E. M., & Putnam, F. W. (1986). Development, reliability and validity of a dissociation scale, Journal of Nervous and Mental Disease, 174, 727-735. Cancienne, J., Cloitre, M., Brodsky, B., & Zeitlin, S. (1993, Nov). Dissociative symptoms in borderline personality disorder. Poster presented at the annual convention for the Association for Advancement of Behavior Therapy, Atlanta. Colligan, R. C., Morey, L. C., & Offord, K. P. (1994). The MMPI/MMPI 2 personality disorder scales: Contemporary norms for adults and adolescents. Journal of Clinical Psychology, 50, 168-200. Demitrack, M. A., Putnam, F. W., Brewerton, T. D., Brandt, H. A., & Gold, P. W. (1990). Relation of clinical variables to dissociative phenomena in eating disorders. American Journal of Psychiatry, 147, 1184-1188. Elliot, D. M., & Briere, J. (1992). Sexual abuse trauma among professional women: Validating the Trauma Symptom Checklist-40 (TSC-40). Child Abuse and Neglect, 16, 391-398. Fahy, T. A. (1988). The diagnosis of multiple personality disorder: A critical review. British Journal o/'P~Tchiatrv, 153, 597-606. Garner, D. M. (1991). Eating Disorder Inventor), 2: Professional manual. Odessa, FL: Psychological Assessment Resources. Garner, D. M., & Garfinkel, P. E. (1979). The Eating Attitudes Test: An index of the symptoms of anorexia nervosa. Psychological Medicine, 9, 273-279. Gartner, A. F., Marcus, R. N., Halmi, K., & Loranger, A. W. (1989). DSM-II1-R personality disorders in patients with eating disorders. American Journal of Psychiatry, 146, 1585 1591. Gleaves, D. H., & Eberenz, K. P. (1995). Assessing dissociative symptoms in eating disordered patients: Construct validation of two self-report measures. International Journal of Eating Disorders, 18, 99-102. Greenes, D., Fava, M., Cioffi, J., & Herzog, D. B. (1993). The relationship of depression to dissociation in patients with bulimia nervosa. Journal of Psychiatrie Research, 27, 133 137. Hathaway, S. R., & McKinley, J. C. (1989). MMPI-2. Manual for administration and scoring. Minneapolis: University of Minnesota Press. Horevitz, R. P., & Braun, B. G. (1984). Are multiple personalities borderline? An analysis of 33 cases. Psychiatric Clinics of North Ameriea, 7, 69-87. Kluft, R. P. (1991). Clinical presentations of multiple personality disorder. Psychiatric Clin&s o/'North America, 14, 605-630. Loewenstein, R. J. (1991). An office mental status examination for complex chronic dissociative symptoms and multiple personality disorder. Psychiatric Clinics of North Ameriea, 14, 567-604. McCallum, K. E., Lock, J., Kulla, M., Rorty, M., & Wetzel, R. D. (1992). Dissociative symptoms and disorders in patients with eating disorders. Dissociation, 5, 227-235. Morey, L. C., Blashfield, R. K., Webb, W. W., & Jewell, J. (1988). MMPI scales for DSM-III personality disorders: A preliminary validation study. Journal of Clinical Psychology, 44, 47-50. North, C. S., Ryall, J. M., Ricci, D. A., & Wetzel, R. D. (1993). Multiple personalities, multiple disorders." Psychiatric classification and media influence. New York: Oxford University Press. Phillips, D. L., & Gleaves, D. H. (1994). The Phillips Dissociation Scale from the MMPI: Further validation. Manuscript submitted for publication. Putnam, F. W. (1985). Dissociation as a response to extreme trauma. In R. P. Kluft (Ed.), Childhood antecedents ~?l'multiple personality. Washington, DC: American Psychiatric Press. Ross, C. A., Joshi, S., & Currie, R. (1991). Dissociative experiences in the general population: A factor analysis. Hospital and Community Psychiatry, 42, 297-301. Spiegel, D. (1993). Dissociation and trauma. In D. Spiegel (Ed.), Dissociative disorders: A clinical review (pp. 117131). Lutherville MD: Sidran Press. Steinberg, M., Cicchetti, D., Buchanan, J., Hall, P., & Rounsaville, B. (1993). Clinical assessment of dissociative symptoms and disorders: The Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D). Dissociation, 6, 3-15. Thelen, M. H., Farmer, J., Wonderlich, S., & Smith, M. (1991). A revision of the Bulimia Test: The BULIT-R. Psychological Assessment: A Journal of Consulting and Clinical Psychology, 3, 119 124. Torem, M. S. (1986). Dissociative states presenting as an eating disorder. American Journal o[' Clinical llvpnosis, 29, 137 142.
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Torem, M. S. (1990). Covert multiple personality underlying eating disorders. American Journal of Psychotherapy, 44, 357-368. Vanderlinden, J., Vandereycken, W., van Dyck, R., & Vertommen, H. (1993). Dissociative experiences and trauma in eating disorders. International Journal of Eatin9 Disorders, 13, 187-193.
J. psychiat.Res., Vol.29, No. 5. pp. 417~126, 1995 Copyright© 1995ElsevierScienceLtd Printedin Great Britain.All rightsreserved 0022 3956/95$9.50+.00
Pergamon 0022-3956(95)00016-X
CORRELATES OF DISSOCIATIVE SYMPTOMS AMONG WOMEN WITH EATING DISORDERS DAVID H. GLEAVES*t and KATHLEEN P. EBERENZt:~ * Department of Psychology, Texas A & M University, College Station, TX 77843, U.S.A.; t Research Department, The Renfrew Foundation, 475 Spring Lane, Philadelphia, PA 19128, U.S.A; and ++Department of Clinical and Health Psychology, Medical College of Pennsylvania and Hahnemann University, Philadelphia PA 19102, U.S.A.
(Received 19 September 1994; accepted 28 February 1995) Summary--We examined the relationship between dissociative symptoms and other Axis I and Axis II symptoms among a sample of 53 women diagnosed as having anorexia nervosa (n = 18), bulimia nervosa (n = 27), or eating disorder NOS (n = 8). Dissociative symptoms were measured by the Dissociative Experiences Scale and the dissociation scale from the Trauma Symptom Checklist40. Severity of dissociative symptoms was generally unrelated to severity of bulimic or anorexic symptomatology but was significantly associated with severity of anxiety and depression. In terms of Axis II symptoms, dissociative symptoms were most highly correlated with schizotypal symptomatology (r = .59), uncorrelated with borderline or antisocial symptomatology, and slightly negatively correlated with histrionic symptomatology.
Introduction Recently, several researchers and clinicians have described or studied dissociative symptoms or dissociative disorders among patients with eating disorders (Demitrack et al., 1990; McCallum et al., 1992; Torem, 1986, 1990, 1993; Vanderlinden et al., 1993). Groups of eating disorder patients have generally been found to exhibit an above normal level of dissociative symptomatology. Less is known about why such symptoms are present and how the dissociative symptoms relate to the other psychopathology of the disorder, including specific eating disorder symptoms (e.g. starvation and bulimia) co-morbid Axis I symptomatology (e.g. depression and anxiety), and Axis II symptomatoiogy. In a previous investigation where the connection between dissociation and other psychopathology among eating disordered individuals was examined, Demitrack et al. (1990) found dissociative symptomatology to be positively correlated with depression, anxiety, self-mutilation, and suicidality. The authors also found no significant differences between anorexia and bulimia nervosa samples in terms of dissociative symptoms; however, they did not did not examine the connection between severity of dissociation and eating disorder symptomatology. More recently, Greenes et al. (1993) also found a significant relationship between depression and dissociation in patients with bulimia nervosa. The authors noted that such an association may confound the previously suggested relationship between bulimia and dissociation. That is, it is unclear whether elevated levels of dissociative Correspondence to: David H. Gleaves, Ph.D., Department of Psychology, Texas A&M University, College Station, TX 77843, U.S.A. 417
418
D.H. Gleavesand K. P. Eberenz
symptoms among eating disordered samples is due to some connection between eating disorders and dissociation per se, or whether such elevations are an artifact of an association between dissociation and depression. Since Demitrack et al. (1990) also reported an association between anxiety and dissociation, anxiety may be another confounding variable. Another relevant and possibly confounding variable may be personality disorder pathology. Personality disorders, especially of a borderline type, commonly occur among patients with eating disorders (e.g. Gartner et al., 1989). Dissociative symptoms may also be associated with certain personality disorders. Severe dissociative symptoms are now included as a diagnostic criterion for borderline personality disorder in the DSM-IV (American Psychiatric Association, 1994). Many researchers and clinicians have also described dissociative symptoms (and dissociative disorders) as being attention seeking and hysterical in nature (e.g. Fahy, 1988) or as being associated with antisocial personality disorders (e.g. North et al., 1993). Thus, if dissociative symptoms are highly associated with such personality disorder pathology, then dissociative symptoms among eating disordered samples may be an artifact of such an association. However, the described associations between dissociative and personality disorder symptomatology have not been demonstrated empirically. In summary, at least two issues regarding dissociative symptoms and eating disorders appear unresolved. It is unclear whether dissociative symptoms reported by eating disordered patients are in some way directly related to the specific psychopathology of eating disorders, or whether elevated levels of dissociative symptoms are due to their association with depression, anxiety, or personality disorder pathology. The nature of the relationship between dissociative symptoms and personality disorder pathology also remains untested. The purpose of the current investigation was to examine empirically the relationship between dissociative experiences and other clinical variables among women with eating disorders. Specific goals were: (1) to determine the specific relationship between dissociative symptoms and anorexic and bulimic symptomatology; (2) to replicate previous findings regarding an association between dissociation and both depression and anxiety; and (3) to examine the association between dissociative symptoms and personality disorder pathology. Method
Subjects Fifty-three women who were in treatment at a residential facility for eating disorders served as subjects. The women's ages ranged from 15 to 50 years, with a mean of 26.5 years and a standard deviation of 7.9. They were diagnosed, based on DSM-III-R criteria (American Psychiatric Association, 1987), as having anorexia nervosa (n = 18), bulimia nervosa (n = 27), or eating disorder NOS (n = 8). Normative data for the sample, based on the Eating Disorder Inventory (see below), are presented in Table 1. By examining percentile scores, one can see that the sample was, for the most part, in the average to slightly above average severity range.
Materials A variety of self-report measures was included in the study. Dissociative symptoms were measured by the Dissociative Experiences Scale (DES; Bernstein & Putnam, 1986) and the
Correlates of Dissociative Symptoms
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Table 1 Subjects' Raw and Percentile Scores on the Eating Disorder Inventor),
AN
BN
EDNOS
DT B BD
16.2 (53) 2.7 (12) 16.9 (49)
16.6 (61) 12.7 (67) 19.8 (60)
10.7 (27) 9.6 (51) 19.9 (60)
I
13.6 (66)
13.0 (62)
12.1 (58)
P ID IA MF
8.5 (54) 8.1 (72) 11.7 (62) 4.1 (65)
10.7 (67) 6.6 (67) 14.3 (70) 4.7 (71)
8.1 (47) 6.1 (60) 8.9 (47) 5.3 (71)
Values in parentheses are approximate percentile scores for eating disordered patients (from Garner, 1991). Dissociation scale from the T r a u m a Symptom Checklist (Elliot & Briere, 1992). These two instruments have been found to demonstrate good convergent validity (r = .73; Gleaves & Eberenz, 1995). Eating disorder symptoms were measured by the Eating Disorder Inventory-2 (EDI-2; Garner, 1991), the Eating Attitudes Test (EAT; Garner & Garfinkel, 1979), and the Bulimia T e s t - Revised (BULIT-R; Thelen et al., 1991). The Beck Depression Inventory (BDI; Beck et al., 1988), and the Minnesota Multiphasic Personality Inventory2 (MMPI-2; H a t h a w a y & McKinley, 1989) were also administered. For this investigation, only the personality disorder scales from the M M P I - 2 (Colligan et al., 1994; Morey et al., 1988) were examined. D a t a based on the clinical scales were presented in a previous investigation (Phillips & Gleaves, 1994). Design and procedures
Patients' diagnoses were made by a masters level admission team member using a semistructured interview. Diagnoses were then confirmed by the patient's individual therapist who was a clinical psychologist or psychiatrist. All of the assessment instruments were included in an intake packet which was administered when the patient was admitted to the hospital. The patients were then instructed to complete the packet during their first few days in the hospital. Results The subjects' scores on the DES and TSC-40-DIS are presented in Table 2a. For descriptive purposes, DES factor scores derived from Ross et al. (1991) are also presented, but were not included in subsequent analyses, since they were not relevant to the specific hypotheses of this study. Total scores for the two dissociation instruments were found to be highly intercorrelated (r = .76), suggesting good convergent validity. The different diagnostic groups were initially compared on the dissociation measures Only data that were relevant to our specific hypothesis were presented. The EDI-2 and TSC-40, EAT, and MMPI-2 contain subscales that were not presented. Information on any of these data can be obtained by contacting the first author.
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using a multivariate analysis of variance (MANOVA). Group means for the two dissociation scales are presented in Table 2b. Based on Wilk's criterion, the MANOVA was non-significant [F(4, 98) = . 14, p > .05], suggesting that the groups did not differ in terms of dissociative symptomsfl Thus, the different diagnostic groups were combined for all subsequent analyses. The univariate relationships between clinical variables were measured via Pearson product moment coefficients (Pearson correlations). Correlations between the dissociation measures and those measuring Axis I symptoms (anorexia, bulimia, depression, and anxiety) symptoms are presented in Table 3. Significance levels at p < .01 and p < .001 are noted. Since several correlations were calculated, a more conservative alpha level was used to control for Type I errors. We then performed a stepwise multiple regression analysis with dissociative symptoms as the criterion and the other symptom variables as predictors. We first created a principal component variable from the DES and TSC-Dissociation scales which was used as the dependent variable in the regression analysis. The two scales were highly correlated (r = .76) and generated a principal component that explained 88% of the variance from the two sales. In the multiple regression analysis, the first variable to enter the equation was the anxiety scale from the TSC-40, since it had the highest zero-order correlation. On the second step, Table 2a Subjects' Range of Scores on the Dissociation Scales
TSC-40-DIS DES Total DES Factor 1 DES Factor 2 DES Factor 3
Mean
SD
Min
Max
6.6 12.5 19.5 2.3 9.7
4.5 12.0 16.8 4.6 15.4
0.0 0.5 0.8 0.0 0.0
18 52.3 72.5 23.8 74.0
TSC-40-DIS, Dissociation scale from the Trauma Symptom Checklist; DES, Dissociative Experiences Scale; Factor 1, depersonalization/derealization; 2, activities in dissociative states; 3, absorption. Table 2b Group Means (and Standard Deviations)for the Dissociation Scales
DES TSC-40-DIS
AN
BN
EDNOS
12.2 (13.8)
13.1 (10.1)
11.2 (11.2)
6.2 (3.9)
6.9 (4.7)
6.5 (5.6)
One reviewer was concerned that meaningful associations between variables might have been obscured by combining all of the subject into one group. For example, this might have occurred if two variables were positively correlated in one sample and negatively correlated in another. To rule out this possibility, we examined all reported correlations separately for the three groups. Although values changes slightly, the pattern of correlations was unchanged, which seemed to justify further the use of the entire sample.
Correlates of Dissociative Symptoms
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Table 3 Correlations Between Dissociative Scales and Other Axis 1 Symptoms Scales DES Anorexia measures E A T Total EDI Drive for Thinness Bulimia Measures Bulimia Test--Revised EDI Bulimia Depression measures BDI TSC-40-DEP Anxiety measures TSC-40-ANX MMPI-MSA
TSC-40-DIS
.25 .25
.43* .38*
.11 .14
.07 .01
.55** .41 *
.52** .44*
.47'* .49**
.68"* .51 **
EAT, Eating Attitudes Test; EDI, Eating Disorder Inventory-2; BUL1T-R, Bulimia Test--Revised. *p < .01; **p < .001.
the BDI was added to the equation. After accounting for these first two variables, all other partial correlations were non-significant. Thus, no other variables were added to the equation. The two variables accounted for 44% of the total variance in dissociative symptoms. Beta weights for the TSC-40 anxiety scale and the BDI were .42 and .32, respectively, suggesting that the anxiety scale contributed greater unique variance. Correlations between the dissociation scales and the personality disorder scales from the MMPI-2 are presented in Table 4. As can be seen, there were numerous significant correlations. We then performed a second stepwise regression analysis using the personality disorder Table 4 Correlations Between Dissociation Scales and MMPI-2 Personality Disorder Scales
MMPI-2 Scale Histrionic Narcissistic Borderline Antisocial Dependent Compulsive Passive Aggressive Paranoid Schizotypal Avoidant Schizoid
DES
TSC-40-DIS
- .26 -.10 .22 .15 .38* .34 .47** .49"* .50** .43* .35
- .36* - .07 .I 1 .13 .23 .38* .53** .45"* .59** .50** .41 *
DES, Dissociative Experiences Scale; TSC-40-DIS, Dissociation scale from the T r a u m a Symptom Checklist. *p < .01; **p < . 0001.
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D . H . Gleaves and K. P. Eberenz
scales as predictor variables. Because of its highest zero-order correlation, the schizotypal scale was the first variable entered into the equation. After accounting for this scale, the passive aggressive scale was entered. After accounting for these two variables, no other partial correlations were statistically significant. Thus, no other variables could be added to the equation. The two variables accounted for 40% of the total variance in dissociative symptoms. Beta weights for the schizotypal and passive aggressive scales were .42 and .30, suggesting that the former contributed greater unique variance in predicting dissociative symptoms. We then performed a third stepwise regression analysis using the four variables that were derived from the first two analyses: the TSC-40 anxiety scale, the BDI, and the schizotypal and passive aggressive scales from the MMPI-2. The anxiety scale was again the first entered in the equation, followed by the schizotypal scale from the MMPI-2. These two variables accounted for 51% of the variance in the dissociative symptoms, and beta weights for the anxiety and schizotypal scales were .45 and .40, respectively, suggesting that they both contributed a sizeable amount of unique variance. After accounting for these two variables, the partial correlations for the other two variables were non-significant.
Discussion A principal goal of this investigation was to examine the relationship between dissociative symptoms and anorexic and bulimic symptomatology. Bulimic behavior appeared to be totally uncorrelated with dissociative symptoms. None of the zero-order correlations was statistically significant (at the predetermined alpha level). Some of the zero-order correlations between the anorexic symptom variables and the dissociation scales were significant. However, after accounting for the depression and anxiety variables (in the stepwise regression procedures) none of the correlations was significant. Thus, these data do not suggest that dissociative symptoms are related to the core symptomatology of eating disorders. The findings support the hypothesis by Greenes (1993) that previously obtained findings may have been confounded. However, the current findings should be interpreted with caution, given the correlational nature of the data. The data suggest that, across a group of eating disordered individuals, severity of dissociative symptoms does not co-vary with severity of eating disordered symptoms. The data cannot be interpreted to mean that individual eating disordered patients do not experience dissociative symptoms associated with bingeing, purging, or other eating disordered behavior. These results did replicate those of Demitrack et al. (1990) regarding the association between dissociation and both anxiety and depression. The results of the third regression analysis found anxiety to be a slightly better predictor of dissociation than was depression. Regarding this high correlation between dissociation and both anxiety and depression, such data might lead one to question (as did one reviewer) whether or not the dissociation scales were actually simply measuring depression or anxiety. That is, do the findings question the construct validity of the dissociation scales? For two reasons, we believe that available data do support the construct validity of the scales. First, the convergent validity coefficient (the correlation between the two scales) was substantially higher (r = .76) than
Correlates of DissociativeSymptoms
423
the correlations between either of the dissociation scales and the depression or anxiety scales (seven out of eight were below .60 and four out of eight were below .50). The only one that was even in the same range was the correlation between the TSC-40-DIS and TSC40-ANX scales (r = .68), which might be somewhat inflated owing to their coming from the same test. The second source of data was a previous study (Gleaves & Eberenz, 1995) in which the construct validity of the same two scales was tested by examining convergent and discriminant validity coefficients (when administered along with instruments measuring other constructs) as well as by factor analytic strategies. The results of both types of analyses supported the construct validity of the two instruments. The current findings regarding the relationship between dissociation and Axis II symptoms were quite interesting. The strongest predictor of dissociative symptoms was the schizotypal scale. This finding was not surprising, given the nature of the items on the scale and the nature of schizotypal symptomatology. Items on the MMPI-2 scale assess odd sensory experiences (e.g. "I have had very peculiar and strange experiences", "I have strange and peculiar thoughts"), depersonalization and derealization ("My soul sometimes leaves my body" and "I often feel as if things are not real") and Schneiderian-type influence phenomena ("Evil spirits possess me at times"), all of which are features generally associated with dissociative disorders (e.g. Loewenstein, 1991). Several of the other personality disorder scales were also significantly correlated with the dissociation measures. However, when stepwise regression procedures were employed, schizotypal appeared to be the strongest predictor. This was not surprising, given the degree of overlap among the scales and constructs. For example, in addition to the symptoms described above, schizotypal personality disorder is characterized by excessive social anxiety and avoidance (which overlaps with avoidant, dependent, and schizoid personality disorders) and suspiciousness (which overlaps with paranoid personality disorder). Thus, the schizotypat scale alone appeared to measure most of the Axis II characteristics that were associated with dissociative symptoms: odd perceptual experiences (including depersonalization/derealization and influence phenomena), excessive anxiety and social avoidance, and distrust of others. The hypothesis that dissociative symptoms are strongly associated with features of borderline or antisocial personality disorders was not supported by these data. Neither of the dissociation measures was significantly correlated with either the borderline or antisocial scales of the MMPI-2. We should note that the failure to find significant correlations with either of these scales was not due to lack of variability on the scales. Both scales were significantly correlated with several of the other personality disorder scales. This finding that the dissociation scales did not correlate with either the borderline or antisocial scales does not suggest that individuals with dissociative disorders cannot have a comorbid borderline or antisocial personality disorder. As with other Axis I conditions, dissociative disorders can be associated with a variety of Axis II symptoms or disorders, and research has shown that dissociative disorders and borderline personality disorder frequently co-occur (e.g. Horevitz & Braun, 1984). However, the finding does suggest that the specific symptomatology of dissociative disorders is distinct from that of borderline or antisocial personality disorders.
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The finding regarding borderline symptomatology is consistent with a recent investigation by Cancienne et al. (1993) who examined dissociative symptoms among patients with borderline personality disorder with and without a history of sexual abuse. Both borderline groups were compared with normal controls. The results suggested that dissociative symptoms were not associated with borderline personality disorder per se, but were associated with a history of sexual abuse. Thus, the findings suggest that dissociative symptoms that have been reported to be associated with borderline personality disorder may actually be an artifact of a comorbid post-traumatic condition. In the current study, both dissociation scales were actually slightly negatively correlated with the histrionic scale (although the correlation was significant for only the TSC-40-DIS). Histrionic personality disorder (formerly termed hysterical personality) is characterized by excessive emotionality and attention seeking (APA, 1994). Thus, the hypotheses that dissociative symptoms are hysterical in nature and that patients with dissociative disorders are frequently attention-seeking individuals were not supported by these data. On the contrary, the negative correlations with the histrionic scale and the positive correlations with the avoidant, schizoid, and schizotypal scales (which are all associated with avoidance behaviors) suggest that (at least within this clinical population) individuals who report dissociative symptoms have more of a tendency towards avoidance and withdrawal. This finding supports the position taken by many clinicians and researchers in the field of dissociation that the dissociative disorders may be clandestine by nature (Kluft, 1991). A limitation of this study was that only one measure of personality disorder symptomatology (the MMPI) was used. Future research could strengthen these findings by using other indices of Axis II symptomatology (e.g. the Millon Clinical Multiaxial Inventory). A larger sample size using other types of clinical and non-clinical subjects would also help to determine the stability and generalizability of the current findings. Another limitation was that structured interviews were not used to determine whether patients met the diagnostic criteria for either dissociative or personality disorders. Thus, the findings only specifically addressed dissociative and personality disorder symptomatology, and we cannot confidently generalize to the issue of dissociative or personality disorders. Future research could attempt to do so using well-validated interview schedules (e.g. Steinberg et al., 1993). A final limitation was that we only examined a linear relationship between dissociative and other experiences. It is possible that other relationships (e.g. curvilinear or quadratic) may exist and may lead to more meaningful interpretations of the data. However, because we had no a priori hypotheses regarding such effect, it was inappropriate to have tested for them since that may have led to spurious findings. Future research might endeavor to test such relationships if theoretical rationale can be presented for doing so. In conclusion, these data somewhat further our current understanding of the phenomenon of dissociation and its relationship with other variables among women with eating disorders. Dissociative symptoms do not appear to be strongly associated with eating disorder symptoms per se, but are associated with a wealth of comorbid Axis I and Axis II symptoms. The associations with Axis II symptoms, however, appear to be different from what has been most commonly hypothesized in the clinical literature.
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